1. Field of the Invention
The present invention relates to a method for producing a cyclic carbamate ester. More particularly, the present invention relates to a method for efficiently producing a cyclic carbamate ester by conducting a reaction using, as starting materials, an organic compound having at least two halogen atoms per molecule, an amine having at least two hydrogen atoms on a nitrogen atom, and carbon dioxide.
Priority is claimed on Japanese Patent Application No. 2004-005353, filed Jan. 13, 2004, the content of which is incorporated herein by reference.
2. Description of Related Art
A cyclic carbamate ester is used as an electrolytic solution in batteries, condensers and capacitors, or is used for cleaning semiconductors. Also, it is used as medicines such as antibiotics.
As a method for producing a cyclic carbamate ester, for example, a method of using an amino alcohol and phosgene is described in Japanese Unexamined Patent Application, First Publication No. Hei 7-59570. Also, a method of using the-amino alcohol, as starting materials, and carbon monoxide, dimethyl carbonate or ethylene carbonate is described in Japanese Examined Patent Application, Second Publication No. Sho 49-116058, Japanese Unexamined Patent Application, First Publication No. Sho 59-222481 and Japanese Unexamined Patent Application, First Publication No. 2002-1050648 respectively. As a method taking account of environmental problems, the reaction of non-toxic carbon dioxide and the amino alcohol is described in Japanese Unexamined Patent Application, First Publication No. 2003-64062, and the reaction of non-toxic carbon dioxide and a cyclic amine is described in Japanese Unexamined Patent Application, First Publication No.2003-96058.
However, because phosgene is a deadly poison, in the case of a method for producing a cyclic carbamate ester using the phosgene, there is a drawback such as limitation in location and the need for safety equipment of the plant for producing a cyclic carbamate. In the case of using the amino alcohol as the starting material, there are drawbacks that the amino alcohol is expensive and that a substitution product of the cyclic carbamate ester must be produced from the amino alcohol. In the case of using carbon dioxide, the same drawback exists when the amino alcohol is used as the starting material, and expensive reagents such as dehydrating agent is required. In the case of using a material having an aziridine structure as the starting material, the material often has high toxicity and has drawbacks in that it is not easily synthesized and is expensive.
In the method for producing a cyclic carbamate ester, effective utilization of cheap and non-toxic carbon dioxide is required. The method for producing a carbamate ester without using an expensive amino alcohol has been scarcely proposed and it has hitherto been required to develop the method. An object of the present invention is to provide the method for producing a cyclic carbamate ester in a safe and inexpensive manner by using the inexpensive and non-toxic carbon dioxide without using an expensive amino alcohol as a starting material of a cyclic skeleton.